Switching power supply circuit using safety Y capacitor
By using the switching quantity transmission loop composed of safety Y capacitors in the switching power supply, the primary switch is directly controlled, which solves the problems of high cost of optocouplers and slow transmission speed, improves loop feedback adjustment performance and reduces standby power consumption.
Patent Information
- Application Number
- CN202421292859.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-06
- Publication Date
- 2025-04-29
- Estimated Expiration
- 2034-06-06
AI Technical Summary
In existing switching power supplies, the cost of optocouplers is high, the transmission speed is slow, and the anti-interference ability is weak, resulting in weak loop feedback regulation performance and high standby power consumption.
The switching quantity transmission circuit consisting of the safety Y capacitor C1 and the safety Y capacitor C2 is used to transmit the pulse shutdown signal generated by the secondary circuit to the primary circuit, and directly control the primary switch to realize the control of the switching duty cycle.
Improves loop feedback regulation performance, reduces standby power consumption, reduces production costs, and simplifies board drawing design and material management.
Smart Images
Figure CN222814386U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of switch power supply control circuits, in particular to a switch power supply circuit using a safety-standard Y capacitor. Background Art
[0002] The switching power supplies currently produced by the industry, such as Figure 1 As shown, the primary circuit and the secondary circuit are connected by a transformer, an optocoupler IC, and a safety capacitor C1, respectively. The optocoupler is used to transmit feedback signals, and the safety capacitor C1 is used to eliminate common-mode voltage. The working principle of the voltage loop feedback is that the secondary circuit converts the output voltage regulation amount from the optocoupler into a current and transmits it to the primary circuit. The primary circuit then generates a corresponding switch duty cycle based on this current to control the output voltage. This transmission scheme belongs to analog quantity transmission. The currently widely used optocoupler cutoff frequency is below 1MHz, the transmission switch amount is small, the speed is slow, the anti-interference is general, and the loop feedback regulation performance is weak. In addition, most of the current of the standby power consumption of the power chip is composed of the analog current transmitted by the optocoupler. The analog current makes the standby power consumption of the power chip higher, and the cost of the optocoupler is higher. Utility Model Content
[0003] The purpose of the utility model is to solve at least one of the technical problems existing in the prior art, and to provide a switching power supply circuit and a circuit using a safety Y capacitor with low cost and capable of enhancing loop feedback regulation performance.
[0004] According to the embodiment of the utility model, a switching power supply circuit using a safety Y capacitor includes a primary circuit, a secondary circuit, and a switch quantity transmission circuit electrically connected to the primary circuit and the secondary circuit respectively, the switch quantity transmission circuit includes a safety Y capacitor C1 and a safety Y capacitor C2, the safety Y capacitor C1 and the safety Y capacitor C2 form a four-terminal network to transmit the pulse shutdown signal generated by the secondary circuit to the primary circuit to directly shut down the primary switch, thereby generating a corresponding switch duty cycle to control the output voltage.
[0005] According to some embodiments of the utility model, the primary circuit includes a primary switch and a control circuit electrically connected to the transformer and the primary switch respectively; the secondary circuit includes a secondary feedback circuit; one end of the safety Y capacitor C1 is electrically connected to a signal receiving end of the control circuit, and the other end of the safety Y capacitor C1 is electrically connected to an output end of the secondary feedback circuit; the safety Y capacitor C1 is used to eliminate the common mode voltage and transmit the pulse shutdown signal; one end of the safety Y capacitor C2 is electrically connected to another signal end of the control circuit, and the other end of the safety Y capacitor C2 is electrically connected to another output end of the secondary feedback circuit; the safety Y capacitor C2 is used to transmit the pulse shutdown signal.
[0006] According to some embodiments of the present invention, the safety-standard Y capacitor C2 is smaller than the safety-standard Y capacitor C1.
[0007] According to some embodiments of the present invention, the ratio of the safety-standard Y capacitor C2 to the safety-standard Y capacitor C1 ranges from 1 / 2200 to 1 / 22.
[0008] According to some embodiments of the present invention, the safety-standard Y capacitor C1 is 2200p, and the value range of the safety-standard Y capacitor C2 is 1-100p.
[0009] According to some embodiments of the present utility model, the primary switch includes a MOS tube Q1, the control circuit includes a primary chip U1, the secondary feedback circuit includes a secondary chip U2, one end of the capacitor C1 is electrically connected to the G pin of the primary chip U1 and the CS pin of the primary chip U1, respectively, the other end of the capacitor C1 is electrically connected to the secondary coil of the transformer and the output end of the secondary circuit, one end of the capacitor C2 is electrically connected to the CH pin of the primary chip U1, and the other end of the capacitor C2 is electrically connected to the CO pin of the secondary chip U2; the gate of the MOS tube Q1 is electrically connected to the output end of the primary chip U1, the drain of the MOS tube Q1 is electrically connected to the primary coil of the transformer, and the source of the MOS tube Q1 is electrically connected to the CS pin of the primary chip U1.
[0010] According to some embodiments of the present invention, the secondary circuit further includes a rectifier circuit electrically connected to the secondary coil of the transformer, and an output end of the rectifier circuit is electrically connected to the secondary feedback circuit.
[0011] The switching power supply circuit using the safety Y capacitor according to the embodiment of the utility model has at least the following beneficial effects: Figure 1 Compared with the traditional solution in , this application changes the optocoupler that transmits analog feedback signals into a switch quantity transmission loop that transmits switch quantity feedback signals composed of safety Y capacitor C2 and safety Y capacitor C1. The switch quantity transmission loop transmits the pulse shutoff signal of the secondary circuit to the primary circuit, and directly turns off the primary switch. In the traditional solution, "on" and "off" are determined by the primary circuit. In this application, the primary circuit only determines "on", and the secondary circuit determines "off". The cutoff frequency of the safety Y capacitor is above 100 MHz. Compared with the analog quantity transmitted by the optocoupler, the safety Y capacitor C2 transmits the switch quantity, which is fast, has strong anti-interference, and enhances the loop feedback regulation performance. In addition, the safety Y capacitor C2 has 2 fewer pads than the optocoupler, and the area occupied by the circuit board is reduced, which is beneficial to the board design; in addition, the safety Y capacitor C2 is the same as the original capacitor C1. Replacing the optocoupler reduces one purchasing category, which is beneficial to material management; and the price of the safety Y capacitor C2 is lower than that of the optocoupler, saving production costs.
[0012] Additional aspects and advantages of the present invention will be given in part in the following description, and in part will become apparent from the following description, or will be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The specific implementation of the utility model is further described below in conjunction with the accompanying drawings;
[0014] Figure 1 This is a schematic diagram of a traditional switching power supply loop;
[0015] Figure 2 It is a schematic diagram of the switching power supply loop feedback;
[0016] Figure 3 is an embodiment of a switching power supply loop feedback. DETAILED DESCRIPTION
[0017] This section will describe in detail the specific embodiments of the utility model. The preferred embodiments of the utility model are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the utility model, but it cannot be understood as a limitation on the protection scope of the utility model.
[0018] In the description of the present invention, it should be understood that descriptions involving orientation, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.
[0019] In the description of the present utility model, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed" etc. are understood to exclude the number itself, and "above", "below", "within" etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.
[0020] Reference Figures 1 to 3The utility model discloses a circuit, comprising a primary circuit 10, a switch quantity transmission loop and a secondary circuit 20. The primary circuit 10 comprises a primary switch and a control circuit 11 electrically connected to a transformer and the primary switch respectively. The secondary circuit 20 comprises a secondary feedback circuit 21. The switch quantity transmission loop comprises a safety Y capacitor C1 and a safety Y capacitor C2. The safety Y capacitor C1 and the safety Y capacitor C2 form a four-terminal network. One end of the safety Y capacitor C1 is electrically connected to a signal receiving end of the control circuit 11, and the other end of the safety Y capacitor C1 is electrically connected to an output end of the secondary feedback circuit 21. The safety Y capacitor C1 is used to eliminate common mode voltage and transmit a pulse shutdown signal; one end of the safety Y capacitor C2 is electrically connected to another signal end of the control circuit 11, and the other end of the safety Y capacitor C2 is electrically connected to another output end of the secondary feedback circuit 21. The safety Y capacitor C2 is used to transmit a pulse shutdown signal.
[0021] The working principle of the circuit is: the primary circuit 10 controls the primary switch to be turned on, the secondary circuit 20 obtains the turn-on time point through the secondary winding of the transformer, the secondary feedback circuit 21 starts timing and determines the corresponding turn-off time to generate a pulse turn-off signal; the safety Y capacitor C1 and the safety Y capacitor C2 form a four-terminal network to form a switch quantity transmission loop; the secondary circuit 20 transmits the pulse turn-off signal to the primary circuit 10 through the switch quantity transmission loop to directly turn off the primary switch, generating a corresponding switch duty cycle to control the output voltage.
[0022] Furthermore, the value of the safety Y capacitor C2 is smaller than the value of the safety Y capacitor C1, and the ratio of the safety Y capacitor C2 to the safety Y capacitor C1 is in the range of 1 / 2200 to 1 / 22. Preferably, the safety Y capacitor C1 is 2200p, and the value of the safety Y capacitor C2 is in the range of 1 to 100p. Since the value of the safety Y capacitor C2 is very small, it does not affect the total amount of cross-connection between the primary side and the secondary side. At this time, the safety Y capacitor C1 has the dual functions of eliminating common mode voltage and transmitting information.
[0023] and Figure 1Compared with the traditional solution in the present invention, the present invention changes the optocoupler for transmitting analog feedback signals into a switch quantity transmission loop for transmitting switch quantity feedback signals composed of safety Y capacitor C2 and safety Y capacitor C1. The safety Y capacitor C2 transmits a pulse shutoff signal to the primary circuit 10 with the help of the safety Y capacitor C1, and directly turns off the primary switch. In the traditional solution, "on" and "off" are determined by the primary circuit 10. In the present invention, the primary circuit 10 only determines "on", and the secondary circuit 20 determines "off". The cutoff frequency of the safety Y capacitor is above 100 MHz. Compared with the analog quantity transmitted by the optocoupler, the safety Y capacitor C2 transmits the switch quantity, which is fast, has strong anti-interference, and enhances the loop feedback regulation performance. In addition, the safety Y capacitor C2 has 2 fewer pads than the optocoupler, and the area occupied by the circuit board is reduced, which is beneficial to the board design; in addition, the safety Y capacitor C2 is the same as the original capacitor C1, and replacing the optocoupler reduces one purchasing category, which is beneficial to material management; and the price of the safety Y capacitor C2 is lower than that of the optocoupler, saving production costs.
[0024] like Figure 3 In some embodiments, the secondary circuit 20 includes a rectifier circuit 22 electrically connected to the secondary coil of the transformer, and the output end of the rectifier circuit 22 is electrically connected to the secondary feedback circuit 21. The primary switch includes a MOS tube Q1, the control circuit 11 includes a primary chip U1, the secondary feedback circuit 21 includes a secondary chip U2, one end of the safety Y capacitor C1 is electrically connected to the G pin of the primary chip U1 and the CS pin of the primary chip U1, the other end of the safety Y capacitor C1 is electrically connected to the secondary coil of the transformer and the output end of the secondary circuit 20, one end of the safety Y capacitor C2 is electrically connected to the CH pin of the primary chip U1, and the other end of the safety Y capacitor C2 is electrically connected to the CO pin of the secondary chip U2; the gate of the MOS tube Q1 is electrically connected to the output end of the primary chip U1, the drain of the MOS tube Q1 is electrically connected to the primary coil of the transformer, and the source of the MOS tube Q1 is electrically connected to the CS pin of the primary chip U1. The secondary chip U2 transmits the feedback signal to the primary chip U1 through the safety Y capacitor C1 and the safety Y capacitor C2 to directly turn off the MOS tube Q1, thereby controlling the output voltage. The safety Y capacitor C2 transmits the switching value with fast speed and strong anti-interference, thereby enhancing the loop feedback regulation performance.
[0025] It is easy for those skilled in the art to understand that the above preferred embodiments can be freely combined and superimposed without conflict.
[0026] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. All equivalent structural changes made using the contents of the present invention specification and drawings under the utility model concept, or directly or indirectly applied in other related technical fields are included in the patent protection scope of the present invention.
Claims
1. A switching power supply circuit using a safety-standard Y capacitor, characterized in that: The invention comprises a primary circuit (10), a secondary circuit (20) and a switch value transmission circuit electrically connected to the primary circuit (10) and the secondary circuit (20) respectively, wherein the switch value transmission circuit comprises a safety Y capacitor C1 and a safety Y capacitor C2, and the safety Y capacitor C1 and the safety Y capacitor C2 form a four-terminal network to transmit a pulse shut-off signal generated by the secondary circuit (20) to the primary circuit (10) to directly shut down the primary switch, thereby generating a corresponding switch duty ratio to control the output voltage.
2. The switching power supply circuit using safety-standard Y capacitors according to claim 1, characterized in that: The primary circuit (10) comprises a primary switch, a control circuit (11) electrically connected to a transformer and the primary switch respectively; the secondary circuit (20) comprises a secondary feedback circuit (21); one end of a safety Y capacitor C1 is electrically connected to a signal receiving end of the control circuit (11); the other end of the safety Y capacitor C1 is electrically connected to an output end of the secondary feedback circuit (21); the safety Y capacitor C1 is used to eliminate common mode voltage and transmit the pulse shutdown signal; one end of a safety Y capacitor C2 is electrically connected to another signal end of the control circuit (11); the other end of the safety Y capacitor C2 is electrically connected to another output end of the secondary feedback circuit (21); the safety Y capacitor C2 is used to transmit the pulse shutdown signal.
3. The circuit according to claim 2, characterized in that: The safety Y capacitor C2 is smaller than the safety Y capacitor C1.
4. The circuit according to claim 3, characterized in that: The ratio of the safety Y capacitor C2 to the safety Y capacitor C1 ranges from 1 / 2200 to 1 / 22.
5. The circuit according to claim 4, characterized in that: The safety Y capacitor C1 is 2200p, and the value range of the safety Y capacitor C2 is 1~100p.
6. The switching power supply circuit using safety-standard Y capacitors according to claim 2, characterized in that: The primary switch comprises a MOS tube Q1, the control circuit (11) comprises a primary chip U1, the secondary feedback circuit (21) comprises a secondary chip U2, one end of a capacitor C1 is electrically connected to a G pin of the primary chip U1 and a CS pin of the primary chip U1 respectively, the other end of the capacitor C1 is electrically connected to a secondary coil of a transformer and an output end of a secondary circuit (20) respectively, one end of the capacitor C2 is electrically connected to a CH pin of the primary chip U1, and the other end of the capacitor C2 is electrically connected to a CO pin of the secondary chip U2; the gate of the MOS tube Q1 is electrically connected to the output end of the primary chip U1, the drain of the MOS tube Q1 is electrically connected to the primary coil of the transformer, and the source of the MOS tube Q1 is electrically connected to the CS pin of the primary chip U1.
7. The switching power supply circuit using safety-standard Y capacitors according to claim 2, characterized in that: The secondary circuit (20) further comprises a rectifier circuit (22) electrically connected to the secondary coil of the transformer, and an output end of the rectifier circuit (22) is electrically connected to the secondary feedback circuit (21).